The Present Disclosure relates generally to a wire-to-board connector and a wire connector, and more specifically to such a connector assembly having a low height and reliable locking structure.
Previously, wire-to-board connectors have been used for connecting electrical wires of a cable to a circuit board such as described in Japanese Patent Application No. 2007-220422. Such a wire-to-board connector has a board connector mounted on the circuit board and engaged by fitting with a wire connector which is connected to an end portion of an electrical wire.
FIG. 16 is an exploded perspective view of a wire connector according to the prior art, in which a wire connector 801 is engaged by a board connector (not shown). A terminal 851 is connected to a termination end of an electrical wire 891 and attached to a housing 811 of the wire connector 801. The housing 811 is formed with a terminal-insertion hole 814, and the terminal 851 is press-fit into the terminal-insertion hole 814. In this way, by fitting the wire connector 801 having the terminal 851 attached thereto so as to be engaged with the board connector, the wire 891 can be connected to a circuit board on which the board connector is mounted, also not shown. Moreover, a locking projection 816 is formed on the housing 811, and this projection 816 is engages a locking portion of the board connector, whereby a stable engagement state can be maintained.
However, in the above-described conventional wire-to-board connector, when the wire 891 is pulled with a strong force when the wire connector 801 and board connector are tightly engaged, there may occur an unfavorable occurrence of the terminal 851 coming loose and pulled from the terminal-insertion hole 814. In order to prevent the removal of the terminal 851, it may be helpful to form a locking projection, called a lance, on an inner wall of the terminal-insertion hole 814 so that the terminal 851 is locked at the latching projection. However, in recent years, connectors have become miniaturized along with the miniaturization of electronic components, devices, and apparatuses. Therefore, the locking projection also has to be extremely small, and moreover, there is a concern that the locking projection itself may be broken when the electrical wire 891 is pulled with a strong force.
The housing 811 which is made of resin is molded, for example, by a molding method that causes molten resin to flow into a mold, like an injection molding. Therefore, the locking projection projected from the inner wall of the terminal-insertion hole 814 is positioned at the inner side of the housing 811, and is thus distant from a gate portion, which is the entrance port of the molten resin into the mold, and is the end point of the flow of the molten resin. For this reason, in such a locking projection, weld lines (sometimes, referred to simply as “welds”) are likely to occur at the converging positions of the flows of the molten resin. In particular, since locking projections are very small and thin, the weld lines are likely to extend in a direction of crossing a cross section thereof.
Moreover, since the weld lines represent interfaces formed because two or more flows of molten resin are unable to reunite, the strength thereof is low. Therefore, when a strong force that pulls the wire 891 is applied to the locking projection via the terminal 851, the locking projection will easily brake at the weld lines. Particularly, when the weld lines are formed at the base end of the locking projection and the vicinity thereof, substantially the entire portions of the locking projection will be lost by the breakage, and thus, the terminal 851 will be removed and extracted from the terminal-insertion hole 814.
It is difficult to prevent the occurrence of the weld lines, and also difficult to control the locations or the extending directions of the weld lines. Particularly, in recent years, the wire connector 801 has been miniaturized and the respective parts of the housing 811 have been made thinner along with the miniaturization of electronic devices and apparatuses. Therefore, it is extremely difficult to control the flow of molten resin so as to prevent the occurrence of weld lines in the locking projection.